Tester

Evaluates one or more tests on a feature, and routes the feature according to the outcome of the test(s).

Typical Uses

Performing quality testing on data
Dividing features into two streams based on a test
Isolating a subset of features based on a test

How does it work?

The Tester accepts any feature. It evaluates each feature against one or more user-defined tests, and outputs the feature via the Passed port if it meets the defined conditions, or via the Failed port if it fails the defined conditions.

The tests are constructed as a series of Test Clauses, which evaluate values or expressions based on a wide range of available Operators and test types. The Test Clauses are connected with Logic - combinations of AND, OR, and NOT, with parentheses to define evaluation order.

Creating Test Clauses

Each clause is composed of a value to test, and the method of testing it. Depending on the type of test, at a minimum the clause will consist of a Left Value and an Operator. If the chosen Operator needs more information (for example, testing for an attribute that is greater than a certain value), a Right Value field is provided.

The Test Clauses are created in a table, and numbered from the top down.

Left Value	Operator	Right Value	Mode*
The value or expression to test	The type of test to perform	The value for comparison, if required by the operator	Test the values in a specific manner
Examples
Latitude	>	49.000001	Automatic
@Area()	In Range	(1,100)	Numeric
SnackType	Like	Kebabs	Case Sensitive
Traffic	Attribute Is Null	<Unused>	Automatic
Count	Type Is	Integer	Automatic

* Note that Mode is only available for individual tests when Comparison Mode is set to Specify Per Test.

Test Clause Operators

See all operators

These are the Operators available for constructing test clauses. They may be used to test attribute values, constructed expressions, constants, and published parameters.

Note that (unless otherwise specified) most operators can be used with both numeric values and strings. Strings may be compared with the =, !=, <, >, <=, and >= operators, and are evaluated by their character codes, so A < B.

Operator

Description

Right Value Configuration

Equal to

Enter a value for comparison.

Not Equal to

Enter a value for comparison.

Less than

Enter a value for comparison.

Greater than

Enter a value for comparison.

Less than or equal to

Enter a value for comparison.

Greater than or equal to

Enter a value for comparison.

In Range

Tests if the value falls within the numeric range specified in set notation.

Open-ended ranges may be defined by leaving either the lower or upper limit blank.

Range values are separated by a comma and enclosed by brackets.

Square brackets - [ ] - indicate inclusive limits (greater than or equal to, less than or equal to).

Round brackets - ( ) - indicate exclusive limits (greater than, less than).

Valid range examples:

(1,9) Greater than 1 and less than 9

[1,9] Greater than or equal to 1 and less than or equal to 9

(1,9] Greater than 1 and less than or equal to 9

(1,) Greater than 1

[,9] Less than or equal to 9

Note This operator is not available when Mode is set to Case Sensitive or Case Insensitive, and those modes are not available when the operator is set to In Range.

Tests if the value may be found in the provided list of possible values and ranges.

Enter any combination of comma-separated strings, numeric values, and/or ranges (in the form of x-y).

Valid configuration examples:

1,10,100

1-99

cat

cat,dog,cats and dogs

dogs,1-9,7

String ranges (for example, a-d) can also be specified. To test for values that contain a hyphen, enclose the value in quotation marks: "LL-27","LL-83".

To test for values that contain either single (') or double (") quotes, enclose the value in the opposing quotes: "Duncan's Lake" or 'Say "Hello"'.

Like

Tests that the value matches a specified string pattern.

Enter a string pattern. Wildcards are supported using the percentage symbol (%), rather than an asterisk (*).

In Automatic mode, this operator is case insensitive. This operator is not available when Mode is set to Numeric.

Example:

If Right Value is %bc%:

abcd: Passed

bc: Failed

Contains

Tests that the Right Value occurs somewhere in the Left Value.

Enter a value to test for.

In Automatic mode, this operator is case insensitive. This operator is not available in Numeric mode.

Example:

If Right Value is bc:

abcd: Passed

abde: Failed

Begins With

Tests that the Left Value string begins with the Right Value string.

Enter the string to be tested against.

In Automatic mode, this operator is case insensitive. This operator is not available in Numeric mode.

Example:

If Right Value is Do:

Dogs: Passed

Cats: Failed

Ends With

Tests that the Left Value string ends with the Right Value string.

Enter the string to be tested against.

In Automatic mode, this operator is case insensitive. This operator is not available in Numeric mode.

Example:

If Right Value is gs:

Dogs: Passed

Cats: Failed

Contains Regex

Tests that the value contains a string that matches a pattern described by a Regular Expression.

Enter a Regular Expression.

The Regular Expression Editor is available via the ellipsis (...) button, and may be used to construct and test expressions.

The regex to test may represent a string to be found anywhere within the value, or may represent the entire value (by creating a regex long enough to represent the extent of the desired value).

Example:

If regex is \d (Any digit)

cats: Failed

9: Passed

cats82: Passed

Type Is

Tests if the value is compatible with the chosen Type.

You may test for multiple types by adding additional Test Clauses.

Select the Type to test for.

Boolean	Valid Boolean values are the strings: TRUE, True, true, YES, Yes, yes, 1 FALSE, False, false, NO, No, no, 0
Double	Floating-point number
Integer	Integer
Numeric	A number (same behavior as Double)
Alphanumeric	All characters are either a digit (0-9) or a letter (a-z, A-Z). White space, nulls, control codes, punctuation, and accented or extended characters are not included.
String	A sequence of characters. The value does not contain any null characters.
XML	Checks for valid XML syntax.
JSON	Checks for valid JSON syntax.

Encodable In

Tests if the value is encodable in the specified encoding without data loss.

Select from a list of standard encodings.

Sample encodings:

Unicode 32-bit(utf-32)
Windows Cyrillic (windows-12510
EBCDIC US (ibm037)

Attribute has a value

Tests that the attribute has a value, and is not null, missing, or empty.

Attribute Is Null

Tests that the attribute has a null value.

Attribute is Empty String

Tests that the value is an empty string.

Attribute is Missing

Tests that the attribute is absent on the feature

Cached Values and Data-Aware Test Clauses

If Feature Caching is enabled, valid attribute values from upstream features can be viewed to complete test clauses.

As shown here in the Tester, if the Left Value has been set to an Attribute Value and the features have been cached, the context menu provides access to the values available in those features. If there are only a few choices, they will be presented in a sub-menu.

If there are a large number of choices, the values will be presented in a Select Value dialog, where the values may be sorted and searched with the Filter option.

Connecting Test Clauses: Logic

Multiple test clauses are connected with Logic, using AND, OR, and NOT in addition to parentheses to specify how the tests are evaluated to determine passing or failing.

Logic connectors can be edited by selecting options in the Logic column of the Test Clauses table, or may be edited directly using the Composite Expression parameter’s Edit button.

Examples

Usage Notes

Due to bulk mode processing, features may appear to output in chunks. Although feature order from a single output port remains intact, when chunks of features are output through both the Passed and Failed ports, unexpected results may occur in workspaces that rely on feature ordering from joined output ports. In these scenarios, we recommend that you do not upgrade the Tester to its 2019.1 or later version, or revise your workspaces so they do not rely on feature ordering from joined output ports. Feature ordering may be specified with the Advanced > Preserve Feature Order parameter.
If you have several Tester transformers in sequence, consider using the TestFilter instead. This transformer allows you to create a series of tests with named output ports for each result.
Note that testing operations are lexical comparisons and not locale-aware.
When filtering out a subset of features, consider the logic of the test(s) when choosing an output port. For example, to remove all of the Dog Parks from a list of parks, you could either:
- Set DogParks=Y, and connect the Failed port (dropping the Passed features), or
- Set DogParks=N, and connect the Passed port (dropping the Failed features).

Configuration

Input Ports

Output Ports

Parameters

Test Clauses

See Creating Test Clauses above for further detail.

Logic

Determines how clauses are evaluated in a composite test.

Note that changes made using the Composite Expression parameter’s Edit function will be reflected in this column once they have been Applied, including the placement of parentheses.

OR	Flexible inclusion: one of the test conditions must be met.
AND	Inclusion: the following test condition must be met.
NOT	Exclusion: the following test condition must not be met.
Parentheses	Used to construct composite expressions, specifying order of clause evaluation.

Left Value

The Left Value may be the value of an attribute, expression, a literal constant, a published parameter or a calculated value that is a combination of the above.

If it is a calculated function or expression, it will be executed for each feature and the result will be used for the test.

Operator

Select the type of test to be performed. Options include:

= (Equal to)
!= (Not equal to)
< (Less than)
> (Greater than)
<= (Less than or equal to)
>= (Greater than or equal to)
In Range
In
Like
Contains
Begins With
Ends With
Contains Regex
Type Is
- Boolean
- Double
- Integer
- Numeric
- Alphanumeric
- String
- XML
- JSON
Encodable In
Attribute has a value
Attribute is Null
Attribute is Empty String
Attribute is Missing

Right Value

Enter any required comparison values or supplementary configuration information for the test selected.

Depending on the Operator chosen, a drop-down list of choices or an ellipses button accessing an additional dialog with correct parameters may become available, to assist in entering values.

Mode

If required, specify a method for evaluating values.

This column is only available when Comparison Mode is set to Specify Per Test.

See Comparison Mode below for available options.

Comparison Mode

Specify a method for evaluating values.

This choice will be applied to all tests, unless Specify Per Test is selected, enabling the Mode column in the Test Clauses table.

Automatic	Compares values as numbers if possible, and strings otherwise.
Numeric	Compares values as numbers if possible, and strings otherwise.
Case Sensitive	Compares values as strings using a case sensitive comparison, and will not attempt numeric conversions.
Case Insensitive	Compares values as strings using a case insensitive comparison, and will not attempt numeric conversions.
Date/Time	Compares values as FME Date/Time values if possible. It can use different mathematical operators such as = (are the two dates the same) or > (is the first date newer than the second). If the input data is not in FME Date format, the comparison will be done as string and an attribute, fme_expression_warnings{} will be added to the feature to indicate this was done. Example: if Mode is set to Date/Time, “20180109141824.9024787-08:00=20180109131824.9024787-09:00” will pass the test.
Specify Per Test	Enables the Mode column, where individual comparison mode selections may be made.

For a string that can be represented as a number such as 4.5 or 4e5, if you set Mode to Automatic or Numeric, it will be treated as a number if the comparison value is also representable as a number.
For example, if Mode is set to Automatic or Numeric, “4E5=400000” will pass the test. If, on the other hand, you want “4E5=400000” to fail the test, set Mode to Case Sensitive or Case Insensitive.

Tip If you know your data is string data, you should set the mode to either Case Sensitive or Case Insensitive. This way, FME does not spend time for each feature to determine if the data is representable as a number, but can just do the string comparison immediately.

Composite Expression

Enabled when multiple test clauses are created.

Enter or edit a test expression that defines the criteria to met in order for a feature to be considered Passed. If edits are made here, the changes will be reflected in the Test Clauses table’s Logic column once the Apply button is used to save changes. Inversely, changes made by selecting Logic options will be reflected here.

Test Clauses are referred to by their number, in the order listed in the Test Clauses table. Clauses may be joined by AND, OR, and NOT, with parentheses.

Example:

((1 AND 2) OR 3)

Interpretation: Clause 1 AND Clause 2 must be true, OR Clause 3 must be true.

See the Composite example above for a use case.

When doing comparisons, null, missing, and empty string values, all evaluate to empty string. Thus, they are considered equal in the context of the comparison operators. Further, the following comparison ordering is respected:

Null, missing, empty string < other values

In Automatic mode, all operators are case sensitive except Like, Contains, Begins With, and Ends With.

Advanced

Preserve Feature Order

This parameter controls the order in which features exit a transformer.

When a transformer has more than one output port, features usually exit one port at a time. At times, it may be useful to keep the order that features arrived in, switching from port to port as necessary. This allows feature order to be preserved, though at a potential cost in processing efficiency.

Select a method for feature ordering.

Per Output Port (Default)

Only preserve the input order of features as they occur within the group of features exiting a given output port.

All features exiting an output port retain their ordering relative to each other (within the group), but not relative to features exiting other output ports.

This option is generally the most efficient, where large chunks of features will exit an output port together (taking advantage of bulk mode).

As features exiting different output ports may not be strictly output in the order they arrived, output ordering may be unpredictable.

Across Output Ports

Strictly preserve the input order of features, regardless of which output port they exit. Features will be output singly in the same order they arrived, switching from port to port as necessary. This option is generally less efficient as the processing gains of bulk mode are less likely to apply - however, feature order is predictable.

Editing Transformer Parameters

Transformer parameters can be set by directly entering values, using expressions, or referencing other elements in the workspace such as attribute values or user parameters. Various editors and context menus are available to assist. To see what is available, click beside the applicable parameter.

How to Set Parameter Values

Defining Values

There are several ways to define a value for use in a Transformer. The simplest is to simply type in a value or string, which can include functions of various types such as attribute references, math and string functions, and workspace parameters.

Using the Text Editor

The Text Editor provides a convenient way to construct text strings (including regular expressions) from various data sources, such as attributes, parameters, and constants, where the result is used directly inside a parameter.

Text Editor

Using the Arithmetic Editor

The Arithmetic Editor provides a convenient way to construct math expressions from various data sources, such as attributes, parameters, and feature functions, where the result is used directly inside a parameter.

Arithmetic Editor

Conditional Values

Set values depending on one or more test conditions that either pass or fail.

Parameter Condition Definition Dialog

Content

Expressions and strings can include a number of functions, characters, parameters, and more.

When setting values - whether entered directly in a parameter or constructed using one of the editors - strings and expressions containing String, Math, Date/Time or FME Feature Functions will have those functions evaluated. Therefore, the names of these functions (in the form @<function_name>) should not be used as literal string values.

Content Types

String Functions	These functions manipulate and format strings.
Special Characters	A set of control characters is available in the Text Editor.
Math Functions	Math functions are available in both editors.
Date/Time Functions	Date and time functions are available in the Text Editor.
Math Operators	These operators are available in the Arithmetic Editor.
FME Feature Functions	These return primarily feature-specific values.
FME Parameters	FME and workspace-specific parameters may be used.
Creating and Modifying User Parameters	Create your own editable parameters.

Dialog Options - Tables

Table Tools

Transformers with table-style parameters have additional tools for populating and manipulating values.

Row Reordering

Enabled once you have clicked on a row item. Choices include:

Add a row
Remove a row
Move current row up one
Move current row down one
Move current row to top
Move current row to bottom

Cut, Copy, and Paste

Enabled once you have clicked on a row item. Choices include:

Cut a row - delete and copy to clipboard
Copy a row to the clipboard
Paste a row from the clipboard

Cut, copy, and paste may be used within a transformer, or between transformers.

Filter

Start typing a string, and the matrix will only display rows matching those characters. Searches all columns. This only affects the display of attributes within the transformer - it does not alter which attributes are output.

Import

Import populates the table with a set of new attributes read from a dataset. Specific application varies between transformers.

Reset/Refresh

Generally resets the table to its initial state, and may provide additional options to remove invalid entries. Behavior varies between transformers.

Note: Not all tools are available in all transformers.

For more information, see Transformer Parameter Menu Options.

Reference

Processing Behavior	Feature-Based
Feature Holding	No
Dependencies	None
Aliases
History	This transformer replaced the AttributeTester and GenericTester transformers.

FME Community

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Search for all results about the Tester on the FME Community.

Examples may contain information licensed under the Open Government Licence – Vancouver, Open Government Licence - British Columbia, and/or Open Government Licence – Canada.